Gesang Cering habitually wakes up at midnight to check whether
his house or sheep pen are flooded again.
He has gone through this late-night routine since 2000, when he
began to see water oozing, or sometimes even spouting from ground,
particularly in winter.
He has also noticed that lake Naigri Puencog, some eight
kilometers from his home village in Nagqu Prefecture, northern
Tibet, often swells beyond what it used to.
Many local herders have witnessed similarly unusual
developments: in many lake areas, water springs out of formerly dry
places.
Even the oldest people in the village cannot explain the
abnormal phenomenon. Some say it's inauspicious and invite lamas to
perform Buddhism rituals, hoping to dispel the evil spirits.
"It's actually caused by global warming," said Bendo, a senior
engineer with Remote Sensing Application Research Center of the Tibet Autonomous Region.
Bendo and his colleagues have been studying the floods in Nagqu
since August 2005. They did site surveys at five lakes in the
prefecture and analyzed changes in the lakes' sizes over the past
two decades with remote sensing mapping.
"We found rises in rainfall as well as in air and ground
temperatures in lake areas, but declines in thickness of snow and
frozen earth," he said. "We therefore decided global warming caused
the lakes to swell."
Bendo said the average water level in Naigri Puencog and two
other inland lakes rose by 12.6 meters in the last 20 years,
flooding an average of 40.8 square kilometers of pasture, cropland
and roads.
Many people say the local climate is milder than before. It gets
warmer and rains more often.
"It's getting more comfortable here," said Zhang Jianhua, who
has been working in Nagqu for 11 years. "The once lifeless hills
are covered in green. We used to wear jackets in summer, but now
shorts and T-shirts are enough."
But experts say the impact of global warming is not always
positive in Tibet. In Ngari Prefecture in western Tibet, for
example, the warm but arid climate has had a negative effect on the
local ecology, Bendo said.
He said, Tibet's response to global warming will provide
valuable clues to climate change research worldwide.
In separate research, Chinese scientists found that glaciers
were melting faster at Mt Qomolangma, known as Mt Everest in the
West.
(Shanghai Daily April 12, 2006)